#### Answer

$x=\pm\sqrt{a}$ or $x=\pm2\sqrt{a}$

#### Work Step by Step

$x^{4}-5ax^{2}+4a^{2}=0$
$(a-x^{2})(4a-x^{2})=0$
$a-x^2=0$ or $4a-x^2=0$
$x=\pm\sqrt{a}$ or $x=\pm2\sqrt{a}$
(We can take the square root of $a$ because it is positive.)

Published by
Brooks Cole

ISBN 10:
1305115546

ISBN 13:
978-1-30511-554-5

$x=\pm\sqrt{a}$ or $x=\pm2\sqrt{a}$

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